Buffer circuit and driver IC

Abstract

Provided is a buffer circuit which realizes a large capacity drive capability and a high-speed output response and realizes reduction of a power consumption, by reducing the current value of a constant-current source in a steady state and adding a circuit for operating so as to supply or absorb load current only at a state change time. This buffer circuit commonly drives a load by an operational amplifying means for buffering an input voltage and outputting the voltage, and an output accelerating means for outputting current larger than current from the amplifying means when the voltage difference of a predetermined offset voltage or higher exists between its input and output voltages. Thus, when the input voltage changes, the current is mainly supplied from the output accelerating circuit to the load until a difference between the input and output voltages becomes a predetermined offset voltage or less, and thereafter the current is supplied to the load so that the input and output voltages from the amplifying means become equal.

Description

technical field [0001] The present invention relates to a snubber circuit using a low current consumption type operational amplifier and a driver IC including a plurality of such snubber circuits. Background technique [0002] Buffer circuits using operational amplifiers are often used in driver ICs for source driving of liquid crystal display devices (LCD), organic EL display devices, and the like. In driver ICs using this buffer circuit, large-capacity drive capability, low power consumption, and high-speed output response are required as the display panel size increases. Moreover, its output voltage must be able to be controlled within a wide range from the ground potential to the vicinity of the power supply potential. [0003] Figure 6 It is a schematic configuration diagram of a conventional (rail-to-rail) operational amplifier 500 (see Non-Patent Document 1). Figure 7 will be Figure 6 The output voltage Vout of the operational amplifier 500 is directly connected ...

AI Technical Summary

Problems solved by technology

In order to achieve low energy consumption, if the current value of the constant current source is reduced, the buffer drive capability will be limited, the rise and fall of the output voltage will take time, and it will be difficult to achieve high-speed output response

However, if the current value of the constant current source is increased, although a high-speed output response can be achieved, the power consumption is increased due to the large current flowing at ordinary times.

Therefore, low power consumption has an inverse relationship with large-capacity drive and high-speed output response. It is difficult to improve both aspects.

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